Sheet feeding apparatus for duplicators



Oct. 11, 1966 H. FENGLER ETAL SHEET FEEDING APPARATUS FOR DUPLICATORS 6Sheets-Sheet 1 Filed Dec. 16, 1964 INVENTOR. HARALD FENGLER KQNRADPHLEPS BY GUNTHER SCHNALL Michel f 172W Oct. 11, 1966 ER ETAL 3,278,181

SHEET FEEDING APPARATUS FOR DUPLICATORS Filed D60. 16, 1964 6Sheets-Sheet 2 INVENTOR. HARALD FENGLER KQNRAD PHLEPS B GUNTHER SCHNALLOct. 11, 1966 H. FENGLER ETAL SHEET FEEDING APPARATUS FOR DUPLIGATORS 6Sheets-Sheet 5 Filed Dec. 16, I964 mm 2 s IN V EN T OR. HARALD FENGLERKQNRAD PHLEPS GUNTHER SCHNALL Oct. 11, 1966 H. FENGLER L SHEET FEEDINGAPPARATUS FOR DUPLICATORS Filed Dec. 16, 1964 6 Sheets-Sheet 4 R SA EP RG ON T. EH5 m DE W mm WWW HKG m/L/m/ w WWW raw,

Oct. 11, 1966 LER ETAL 3,278,181

SHEET FEEDING APPARATUS FOR DUPLICATORS Filed Dec. 16, 1964 6Sheets-Sheet 5 IN VEN TOR.

HARALD FENGLER KQNRAD PHLEPS BY GUNTHER SCHNALL [by/L 4.12: AG/e,-

Oct. 11, 1966 FENGLER ETAL 3,278,131

SHEET FEEDING APPARATUS FOR DUPLICATORS Filed Dec. 16, 1964 6Sheets-$heet 6 INVENTOR.

HARALD FENGLER KQNRAD PHLEPS BY GUNTHER SCHNALL United States PatentOfiice 3,278,181 Patented Oct. 11, 1966 3,278,181 SHEET FEEDINGAPPARATUS FOR DUPLICATORS Harald Fengler, Munich, Konrad Phleps,Grunwald, and Giinther Schnall, Munich, Germany, assignors to AgfaAktiengeselischaft, Leverkusen, Germany Filed Dec. 16, 1964, Ser. No.418,638 Claims priority, application Germany, Dec. 20, 1963, A 44,853 30Claims. (Cl. 27122) The present invention relates to printing machinesin general, and more particularly to an improved sheet feeding apparatusfor duplicators and similar printing or reproducing machines.

An important object of the invention is to provide a relatively simpleapparatus which can be readily adjusted to accommodate stacks ofdifferent height, width or length and which can be adjusted to feedsheets of different consistency.

Another object of the invention is to provide a sheet feeding apparatuswhose parts may be collapsed to form a compact unit which may be storedin a small area and which may be collapsed only when its cornerseparators and other sensitive components are protected againstdeformation and/or other damage.

A further object of the invention is to provide a sheet feedingapparatus wherein the corner separators are guided and mounted in such away that each thereof assumes an optimum position with reference to theuppermost sheet of a stack regardless of the height and other dimensionsof the stack.

An additional object of the invention is to provide improved supportsfor the corner separators of a sheet feeding apparatus.

A concomitant object of our invention is to provide improved carriersfor the elements which feed the sheets from the stack on to the printingmechanism of a duplicator.

Still another object of the invention is to provide improved adjustingmechanisms which regulate the pressure between the uppermost sheet of astack and the elements which feed sheets from the stack on to theprinting mechanism.

Another object of the invention is to provide a sheet feeding apparatuswherein the corner separators are assembled, configurated and mounted insuch a way that they automatically move to optimum positions ofengagement with the uppermost sheet when the operator decides to inserta fresh stack of sheets into the space from which the sheets are beingfed seriatim to the printing mechanism of a duplicator or anotherprinting or reproducing machine.

A further object of our invention is to provide a sheet feedingapparatus wherein the elements which actually displace the uppermostsheets of a stack control such movements of the sheet feeding apparatuswhich are necessary to compensate for gradual reduction in the height ofa stack when the printing machine is in actual use and recieves sheetsfrom the feeding apparatus.

Still another object of our invention is to provide a sheet feedingapparatus wherein the supports for the corner separators are readilydetachable and/or adjustable into optimum positions for engagement withthe sheets of a fresh stack.

Another object of the invention is to provide a sheet feeding apparatuswhich can be readily attached to or otherwise combined with many typesof presently utilized printing mechanisms in a duplicator or anotherprinting machine.

A further object of the present invention is to provide an improved feedtable which may be used in a sheet feeding apparatus of the aboveoutlined characteristics and to assemble the feed table in such a waythat it may be readily moved with reference to and/or detached from thehousing of a duplicator.

Briefly stated, one feature of our invention resides in the provision ofan apparatus for feeding sheets to the printing mechanism of a printingmachine. The apparatus comprises a feed table having a platform forsupporting a stack of sheets, a pair of side rails mounted on the feedtable for lateral movement toward and away from the sides of a stacktherebetween, feeding means preferably including one or moreroller-shaped feed members for feeding the uppermost sheets from thestack which rests on the platform, a pair of corner separators eachincluding a substantially horizontal lip arranged to overlie theuppermost sheet of the stack at one front corner thereof and asubstantially vertical stop disposed ahead of the corresponding frontcorner of the uppermost sheet, and coupling assemblies articulatelyconnecting each corner separator to one of the side rails in such a waythat the corner separators descend by gravity in a plane which issubstantially normal to the platform when the height of the stack on theplatform decreases.

In accordance with a more specific feature of our invention, eachcoupling assembly may include an elongated supporting arm which isdetachably secured to the corresponding corner separator and is providedwith an elongated slot which receives a pivot pin mounted on therespective side rail so that the supporting arms are pivotable about andmay perfonrn at least some longitudinal movements with reference to thepivot pins. Each supporting arm carries a follower which extends into asuitable cam slot provided in the corresponding side rail and serving toallow for automatic gravitational descent of the corner separators inresponse to decreasing height of the stack on the platform whereby thecam slots guide the supporting arms in such a way that the cornerseparators descend in a plane which is substantially normal to theplatform, i.e., the position of the stops on the corner separators withreference to the uppermost sheet of the stack will remain substantiallyunchanged regardless of the momentary height of the stack. It is clearthat the followers may be mounted on the side rails and that the camslots may be provided on the supporting arms. This would amount to asimple reversal of functions.

The novel features which are considered as characteristic of theinvention are set forth in particular in the appended claims. Theimproved printing machine itself, however, both as to its constructionand its mode of operation, together with additional features andadvantages thereof, will be best understood upon perusal of thefollowing detailed description of certain specific embodiments withreference to the accompanying drawings, in which:

FIG. 1 is a fragmentary side elevational view of a portion of a printingmachine whose sheet feeding apparatus is constructed and assembled inaccordance with a first embodiment of our invention, certain parts ofthe machine being shown in part diagrammatically and in part brokenaway;

FIG. 2 is an enlarged fragmentary perspective view of the front portionof a feed table which forms part of the improved sheet feedingapparatus;

FIG. 3 is a transverse vertical section through the feed tablesubstantially as seen in the direction of arrows from the line III-IIIof FIG. 1 and shows one of the side rails in folded position;

FIG. 4 is a fragmentary transverse section as seen in the direction ofarrows from the line IV-IV of FIG. 1 and illustrates one form ofadjustable mechanism which serves to regulate the pressure between thefeed members and the uppermost sheet of a paper stack;

FIG. illustrates the feed table in idle position in which its platformis located in a substantially vertical plane;

FIG. 6 illustrates a safety device which serves to prevent folding ofthe associated side rail when the corner separator is still in operativeposition;

FIG. 7 is a fragmentary longitudinal vertical section substantially asseen in the direction of arrows from the line VII-VII of FIG. 2 andillustrates one of the corner separators in operative position while thefeed table assumes its lower end position in which the platform mayreceive a fresh stack of paper sheets on top of the remainder of thepreceding stack;

FIG. 8 is a fragmentary side elevational view of a modified printingmachine wherein the feed members are biased by adjustable torsionsprings; and

FIG. 9 is a section as seen in the direction of arrows from the lineIXIX of FIG. 8.

Referring first to FIGS. 1 to 3, there is shown a printing machine whichcomprises a housing including an upright wall 1 provided with a verticalslot 1a which guides two pins or studs 2a, 2b mounted on a dependingside wall or skirt 2 forming part of a vertically reciprocable feedtable 2. The feed table comprises a second side wall or skirt 2 whosepins are guided in the vertical slot of a second upright wall 1, andthis second side wall 2" is connected to the side wall 2 by a series ofspacer bolts (not shown) as well as by a transversely extendinghorizontal shaft 3. The feed table 2 further includes a tiltableplatform 4 having two depending lateral panels 4 and being rockableabout the axis of the shaft 3. The platform 4 is provided with forwardlyextending projections 4a which normally engage stop pins 20 mounted onthe side walls 2, 2". When the projections 4a engage the correspondingstop pins 2c, the platform 4 is in proper position to receive a stack ofsheets. The side walls 2', 2 and the shaft 3 form a frame orsubstructure of the feed table 2 whose superstructure consists of theplatform 4.

A manually operable actuating member or knob 5 is provided with aknurled peripheral portion 5a and includes an internally threadedcylindrical portion 5b which meshes with the externally threaded endportion 7a of a transversely extending horizontal spindle 7. Theactuating knob 5 is rotatable in one of the panels 4' and is retainedtherein by a split ring 6, shown in FIG. 3. The ring 6 may be insertedor removed through a slot 4b provided in the left-hand panel 4, as theparts appear in FIG. 3, and serves to prevent axial displacements of theactuating knob 5. A second split ring 8 is mounted at that end of thethreaded portion 7a which extends beyond the threaded portion 5b of theactuating knob 5 and serves to prevent complete withdrawal of thespindle 7. This spindle supports two mounting brackets 9 in such a waythat each mounting bracket can be made to move axially of and to rotateabout the spindle or, better to say, that the spindle can rotate in themounting brackets. The upper portions or heads 9b of the mountingbrackets 9 extend upwardly and through transverse apertures 40 providedin the top plate 4d of the platform 4. The apertures 40 are configuratedin such a way that they guide the heads 9b of the corresponding mountingbrackets during axial movement with reference to the spindle 7. The legs9a of the mounting brackets 9 are located at a level beneath the topplate 4d and are mounted directly on the spindle 7. Clamping screws 10serve to secure the mounting brackets 9 to the spindle 7, and the milledheads of these clamping screws extend above the top plate 4d to bereadily accessible for manipulation by the operator of the printingmachine. The tips of the screws 10 may engage the spindle withsufficient friction to prevent any uncontrolled movements of themounting brackets.

Each arm 9a carries a horizontal pivot pin 11 for one of two side rails12 which may be rotated in vertical planes about horizontal axesextending at right angles to the axis of the spindle 7, see FIG. 3. Themeans for detachably securing the pivot pins 11 to the correspondingarms 9a comprises suitable split rings or the like, not shown in thedrawings. When the side rails 12 are moved to their operative positionsas shown for the left-hand side rail 12 of FIG. 3, their lower edgefaces 12a abut against the heads of stop screws 13 which are driven intothe corresponding mounting brackets 9 and are rather difficult to turnso as to provide reliable abutments for the associated side rails and tohold them in operative positions. When a side rail 12 is pivoted to theinoperative or folded position, shown in the right-hand portion of FIG.3, it may come in actual abutment with the upper side of the top plate4d.

By releasing the clamping screws 10, the operator is in a position tomove the mounting brackets 9 toward or away from each other by shiftingthe arms 9a along the spindle 7. Such adjustment will be necessary inorder to move the side rails 12 laterally and into actual abutment withthe sides of a stack 21 which rests on the top plate 4d between themounting brackets 9. When the clamping screws 10 are applied withrequisite force, the spindle 7 cannot rotate and, by rotating theactuating knob 5, the operator is in a position to shaft the spindleaxially, together with the mounting brackets 9, screws 10, pivot pins 11and side rails 12.

Each side rail 12 carries a horizontal pivot pin 14 which is coupledwith the rear end portion of an elongated supporting arm 15. The rearend portions of the arms 15 are provided 'with elongated closed slots15a which receive the pins 14 so that each supporting arm may pivotabout and is free to move, within limits, radially of the correspondingpin 14. The front end portions of the supporting arms 15 carry cornerseparators 16. Each supporting arm includes a pin-shaped follower 18which extends into and tracks the walls surrounding an arcuate cam slot17 provided in the corresponding side rail 12. The configuration of eachcam slot 17 is such that the corresponding corner separator 16 moves ina vertical plane when the follower 18 tracks the walls surrounding therespective slot 17 while the rear end portion of the arm 15simultaneously pivots and slides with reference to the pin 14. In otherwords, the corner separators 16 will move up or down in response to acomposite movement of the associated supporting arms 15, and suchcomposite movement includes a pivotal movement about the pin 14 andsimultaneous longitudinal displacement with reference to this pin.Lateral movements of the supporting arms 15 are restricted by platelikeguides 12b which are mounted on or form part of the corresponding siderails 12.

Each cam slot 17 communicates with a further cam slot 19 which mayreceive the corresponding follower 18 when the supporting arms 15 are tobe moved into retracted or inoperative positions indicated in FIG. 1 byphantom lines 15. When the operative position, i.e., when the followers18 extend into the cam slots 17, the corner separators 16 will travel upand down in a vertical plane indicated in FIG. 1 by a heavy phantom lineII. More particularly, the corner separators will move in a plane whichis substantially normal to the plane of the top plate 4d. When ininoperative position, the tips 16a of the corner separators 16 arewithdrawn sufiiciently to bypass the adjoining stationary parts of theprinting machine when the side rails 12 are pivoted to their collapsedor folded positions (see the right-hand portion of FIG. 3). As shown inFIG. 3, the followers 18 may extend outwardly and well beyond the outersides of the rails 12 to serve as handgrip members which may bemanipulated by fingers when the supporting arms 15 are to be moved intotheir phantom-line retracted or inoperative positions 15. As a rule, thecam slots 19 will be configurated in such a way that they insure smoothtransfer of followers 18 from the corresponding cam slots 17 and equallysmooth descent of supporting arms 15 toward the upper side of the topplate 4d. The lowermost portions of the slots 19 may be straight orsubstantially straight.

Each corner separator 16 is provided with an elongated open slot 16dwhich receives the stems of two fastening screws b, 15c serving tosecure it to the front end portion of the corresponding supporting arm12. Each corner separator further comprises a substantially horizontalseparator lip 1612 located rearwardly of the tip 16a and a generallyvertical front stop 160. The lips 16b overlie the front corners of theuppermost sheet of the stack 21 which is placed onto the top plate 4d,either due to the weight of the corresponding supporting arm 15 or dueto the provision of a weight 21 which is detachably fastened to thesupporting arm by a screw a or the like. Thus, each supporting arm 15actually resembles a lever whose fulcrum is at 14 and whose righthandend portion (carrying the coner septrator l6 and weight 20) is so heavythat the lip 16b of the corner separator rests on the uppermost sheet ofthe stack 21 shown in FIG. 1. The screws 15b, 15c allow for adjustmentof corner separators 16 longitudinally of the associated supporting arms15 or for complete detachment of the corner separators. When the lips16b rest on the front corners of the uppermost sheet of the stack 21,the front stops 160 are located just ahead of the respective frontcorners at the front side of the stack and prevent any shifting ofuppermost sheets in forward direction. Each corner separator 16 may bereadily detached to be replaced by a different corner separator whichmight be better suited for use in connection with a certain type ofpaper. For example, the printing machine may be furnished with a set ofcorner separators having lips 16b of different length or area so thatsuch lips will overlie a larger or smaller portion of the uppermostsheet in the stack 21. The front stops 16c extend downwardly from thefront edges of the lips 16b, see particularly FIG. 2.

The uppermost sheet of the stack 21 is engaged by a pair of feed rollers22 (only one showvn) which are mounted on plate-like carriers 23. Thecarriers 23 are rockable on horizontal shafts 24 each of which supportsa driver gear 25. The gears 25 are rotated by the drive mechanism of theprinting machine in a manner well known per se, for example, through theintermediary of a freewheel clutch, and each driver gear 25 meshes withan intermediate gear 26 which drives a pinion 27 on the shaft of thecorresponding feed roller 22. The feed rollers 22 are drivenintermittently in synchronism with the operation of the printingmechanism so as to feed the sheets at requisite intervals as will bedescribed later. Thus, whenever the feed rollers 22 rotate in a sense toshift the uppermost sheet of the stack 21 in a direction to the right,as the parts appear in FIG. 1, the front edge portion of the topmostsheet bulges upwardly because it is held by the lips 16b and front stops160 of the corner separators 16 until its bulge increases sufficientlyto snap out of the corner separators and to straighten out whereby thefront edge portion advances beyond the front side of the stack 21 and isready to be engaged by the transfer mechanism which feeds it on to theprinting station.

The pressure of the feed rollers 22 and the pressure of the cornerseparators 16 will be adjusted to suit different grades of paper.

In accordance with a feature of the present invention, the pressure offeed rollers 22 upon topmost sheet of the stack 21 may be adjusted in anumber of ways. As shown in FIGS. 1 and 4, the carriers 23 support anauxiliary weight in the form of a hollow cylindrical roll 28 whose endportions receive two outwardly extending pins 29 having pistons 29abiased by a helical expansion spring 29b. Each carrier 23 is providedwith a series of holes 23a23e each of which may receive one of the pins29. Each of these holes is machined at a different distance from thecorresponding shaft 24 so that the pressure of the feed rollers 22 uponthe uppermost sheet of the stack 21 varies when the pins 29 arewithdrawn from the holes 23a and are inserted into another pair ofaligned holes 23b, 23c, 23d or 23e. In other words, by transposing thepins 29 into a different pair of aligned holes in the carriers 23, theoperator may select the pressure exerted by the feed rollers 22 upon theuppermost sheet of the stack 21. Such pressure must be changed when thefriction between the sheets of the fresh stack is different from thefriction between the sheets of the preceding stack or when the frictionbetween the peripheral surfaces of the feed rollers 22 and the sheets oftwo consecutive stacks is different. The rollers 22 may consist ofrubber or other elastomeric material, either entirely or at least inpart. FIGS. 8 and 9 illustrate a different arrangement which enables theoperator to change the pressure of feed rollers 22 up'on the uppermostsheet of the stack. The shaft 24' of the driver gear (not shown)supports a modified pivotable carrier 23 which is connected with apermanently or detachably mounted weight 30 here shown as a roll locatedabove the feed roller 22. The pressure transmitted by the weight 30 isconstant but the pressure of the feed roller 22' may be varied by atorsion spring 31 which is convoluted around a cylindrical sleeve orreel 31a surrounding the shaft 24'. One end portion 31b of the spring 31is secured to a disk 32 which is provided with a concentric arcuate slot3 2a and is angul arly adjustably fixed to the carrier 23' by a bolt 34and nut 34a. The other end portion 31c of the spring 31 engages anactuating lever 33 having a knob 33a which extends upwardly beyond afixed supporting member 101. The optimum initial pressure of the feedroller 22 is selected by angular adjustment of the disk 32 withreference to the carrier 23'. Once the disk 32 is moved to requisiteangular position, the bolt 34 is passed through a bore in the carrier 23and is fixed in position by the nut 34a so that the disk 32 remainsattached to the carrier. In the meantime, the lever 33 remains in thestarting position of FIG. 8 in which the head of a locating or arrestingscrew 35 extends into the leftmost enlarged portion 36a of an arcuateslot 36 provided in the supporting member 1101. It will be readilyunderstood that the bias of the torsion spring 31 changes if the knob33a is shifted in the direction indicated by the arrow 33b (see FIG. 3)to withdraw the head of the screw 35 from the enlarged portion 36a, andif the lever 33 is thereupon pivoted to move the head of the screw 35into one of the enlarged portions 36b-36e. The center of curvature ofthe slot 36 is located on the axis of the shaft 24'. Thus, bymanipulating the lever 33, the operator may change the pressure betweenthe feed roller 22 and the uppermost sheet of the stack 21. Suchpressure will be varied for reasons which were explained in connectionwith FIG. 4. It is clear that the slot 36) may be provided with two,three, four or more than five enlarged portions, depending on thedesired number of adjustments in the pressure of the feed rollers 22.The same holds true [for the number of holes in the carrier 23 shown inFIGS. 1 and 4. The lever 33 is resilient and tends to assume a positionin which the head of the locating screw 35 extends into one of theenlarged portions 3611-362. It is further clear that the other carrier23' (not shown in FIGS. 8 and 9) is provided with a similar pressureadjusting arrangement including a second spring 31 and a second lever33.

Referring again to FIG. 1, the lifting mechanism for the feed table 2 isdriven by a cam 37 which rotates at a constant speed to reciprocate avertical push rod 38 guided in bearings 38a. The upper end of the pushrod 38 engages a projection or nose 39a provided on a rockable lever 39and can turn this lever in a counterclockwise direction against the biasof a return spring 40 which simultaneously compels the lower end of thepush rod 38 to track the face of the cam 37. When the spring 40 is freeto contract (i.e., when the push rod 38 performs a return stroke indownward direction, as viewed in FIG. 1), the lever 39 may cause aratchet wheel 42 to rotate by a step in a clockwise direction. Theratchet Wheel 42 is engaged by the pallet of a pawl 43 which ispivotably secured to the lever 39 and is biased against the ratchetwheel by a torsion spring 41. The ratchet wheel 42 is connected with acoaxial pinion 44 which meshes with a vertical rack 20. provided on thedownwardly extending side wall 2 of the feed table 2. The pinion 44 canlift the feed table whenever the push rod 38 performs a return stroke.

' The lever 39 also performs a second function, namely, it causes thefeed table 2 to rise at a rate which is proportional to changes inangular position of the carrier 23 such as will result from a reductionin the height of the stack 21. The carrier 23 comprises a projection ornose 23 which extends forwardly and is engaged by the left-hand arm of atwo-armed lever 45 mounted on a pivot pin 45a which is secured to thewall 1 or to another stationary part of the housing. The right-hand armof the lever 45 is biased by a spring 45b which tends to maintain thelever in abutment with a stop pin 45c mounted on the wall 1. Theright-hand arm of the lever 45 is iartieulately connected with asubstantially vertical link 47 having a vertical face 47 which abutsagainst a stationary stop pin 46. When the feed roller 22 is raised,i.e., when the stack 21 is high, a pin or stud 39b at the upper end ofthe lever 39 engages the lowermost (left-most) serration 47a at thelower end of the link 47. When the height of the stack 21 is reduced andthe feed roller 22 descends to a lower level, the projection 23 of thecarrier 23 rocks the lever 45 in a clockwise direction, as viewed inFIG. 1, whereby the link 47 descends and the pin 39b comes in engagementwith the next higher serration at the lower end of the link 47.Consequently, the lever 39 may turn through a larger angle and effects alarger upward movement of the stack 31 by allowing the pinion 44 torotate through a greater angle. The lifting action of the lever 39 willincrease stepwise when the pin 39b will be free to engage the nexthigher seration and such lifting action will be greatest when the pin39b engages the topmost serration 47d.

A locking pawl 48 is rockable about a pin 48c and is biased by a torsionspring 49 so that its pallet engages the ratchet wheel 42 and preventsrotation of the pinion 44 when the lever 39 rotates in acounterclockwise direction. During such rotation of the lever 39, thepallet of the pawl 43 simply rides over the teeth of the ratchet wheel42. The pawl 48 is provided with an outwardly extending tongue 48a whichserves as a handgrip member and is used to disengage the pawl 48 fromthe ratchet wheel 42 so that the feed table 2 may descend to its lowerend position when the operator desires to insert a fresh stack 21. Whenthe tongue 48a is depressed, a sickle-shaped motion transmitting portion48b of the pawl 48 engages a pin 43a on the pawl 43 and moves the latterout of engagement with the ratchet wheel 42. When the feed table 2returns to the lower end position, the pin 2a abuts against the bottomwall of the vertical slot 1a. If the just described mechanism isequipped with a friction brake or with another device which preventsautomatic descent of the feed table 2 in response to disengagement ofpawls 43, 48 from the ratchet wheel 42, the shaft of the pinion 44 isrotated by a handwheel 50 shown in FIG. or by another suitable manuallyoperated device. Once the feed table 2 reaches its lower end position inwhich the pin 2a is moved to the position shown in FIG. 1, the operatoris free to place a fresh stack 21 onto the top plate 4d of the platform4.

In response to rotation of the handwheel 50 in the opposite direction,the feed table 2 is returned to an intermediate position in which thefeed rollers 22 bear against the uppermost sheet of the freshly insertedstack 21 while the corner separators 16 engage the front corners of theuppermost sheet. Alternatively, the mechanism shown in the right-handpart of FIG. 1 will automatically lift the stack to a predeterminedlevel when the printing machine is started. When the feed rollers 22 areout of contact with the stack 21, the carriers 23 rest on stop pins 51which are secured to the housing of the printing machine and the pin 39bof the lever 39 cooperates with the topmost serration 47d on the link47. Consequently, the feed table 2 rises rapidly to move the uppermostsheet to a predetermined level and into actual engagement with the feedrollers. It is clear that such lifting of the feed table 2 is necessaryonly when the height of a fresh stack 21 does not sufiice to keep theuppermost sheet in contact with the feed rollers 22 while the pin 2a ismoved to the position shown in FIG. 1.

The insertion of a fresh stack 21 is further facilitated by theprovision of a stop for the front side of the stack. This stop isprovided on the vertical front wall 52a of the housing. Thus, even ifthe operator is careless and simply shoves a fresh stack into the spacebetween the side rails 12, the front side of the stack will come inabutment with the front wall 52a and all of the sheets will remain inproper overlapping position with reference to each other. It will benoted that at least a portion of the front wall 52a is nearer to thefront side of the stack 21 than the vertical stops 160. The height ofthe front wall 52a is less than the height of a fresh stack 21 (see FIG.2) so that the uppermost sheet, and a few sheets which are locateddirectly below the uppermost sheet, will abut solely against thevertical front stops of the corner separators 16. Once the uppermostsheet is caused to skid over the lips 16b of the corner separators, itsfront edge portion overlies the rearmost part of a horizontal plate 52which extends forwardly from the upper end of the front wall 52a. Thelateral portions 52a of the front wall 52a are offset forwardly withreference to the remainder of the front wall to provide room for thecorner separators when the height of the stack 21 decreases. However,when the height of the stack 21 decreases below a minimum permissiblelevel, the tips 16a of the corner separators come to rest on thelaterally extending end portions 52b of the horizontal plate 52 andprevent further descent of the corner separators. Thus, when inserting afresh stack, the operator need not lift the corner separators 16 becausethey are lifted automatically by the uppermost sheet of the fresh stackwhich slides beneath the lips 16b. The same applies for the feed rollers22 which are held against further descent when the correspondingcarriers 23 abut against the fixed stop pins 51 shown in FIG. 1. Whenthe operator inserts a fresh stack, the feed rollers 22 are lifted in afully automatic way and come to rest on the uppermost sheet. Of course,this holds true only if the height of the freshly inserted stack issufficient to rise to the level at which the feed rollers 22 are locatedwhen the carriers 23 abut against the stop pins 51.

The printing machine of our invention further comprises locking orblocking means to prevent folding of side rails 12 over the top plate 4dof the platform 4 when the tips 16a of the corner separators 16 rest onthe end portions 52b of the horizontal plate 52. Such folding coulddestroy or deform the corner separators, and the just mentioned blockingmeans serves as a safety device to insure that the operator is free tofold the side rails 12 only at the time the supporting arms 15 areretracted to the phantom-line positions 15'. Each safety device includesa lever 53, shown in FIGS. 6 and 7, which is pivotable about ahorizontal pin 54 mounted on the corresponding side rail 12. The lever53 has a cam face 53a which is located in the path of the follower .18when the latter is caused to advance toward the lower end of the camslot 19. The tip of the lever 53 carries a hook 53b which normallyextends into a cutout 56 of the corresponding mounting bracket 9 andengages the underside 56a of this bracket. The lever 53 is biased by aspring 55 so that its hook 53b is normally in engagement with theunderside 56a but is disengaged therefrom when the follower 18 slidesalong the cam face 53a. In FIG. 6, the hook 53b is disengaged from theunderside 56a because the follower 18 approaches the lower end of thecam slot 19.

FIG. 3 shows that the pivot pins 11 for the side rails 12 are offsetinwardly with reference to the general planes of the corresponding siderails so that, when a side rail begins to move to the folded positionshown for the right-hand side rail of FIG. 3, its lower edge face 12afirst travels substantially vertically upwardly (because it is locatedat a distance from and outwardly of the pivot pin 11) and thereuponbegins to move toward a vertical plane. Since the levers 53 areimmediately adjacent to the major portions of the side rails 12, theyare spaced outwardly from the pivot pins 11 when the corresponding siderails are held in vertical positions so that their hooks 53b prevent anypivoting of the side rails before the followers 18 are moved into thelower ends of the cam slots 19.

The lower end of each cam face 53a is adjacent to a substantiallysemicircular recess or dwell formation 530 which receives thecorresponding follower 18 when the associated supporting arm 15 is movedto the retracted position 15. The levers 53 then lock the supportingarms 15 in such positions but may be disengaged therefrom if theoperator applies a sufficient force to overcome the bias of the springs55 by causing the followers 18 to travel upwardly toward the junctionsbetween the cam slots 17, 19. This will be done after the side rails 12are folded back to their operative vertical positions and when theoperator wishes to move the tips 16a of the corner separators intoabutment with the end portions 52b of the horizontal plate 52.

When the side rails 12 are folded over the top plate 4d of the platform4, the entire platform may be pivoted about the axis of the shaft 3 andtakes the position shown in FIG. in which the top plate 4:1 is locatedin a substantially vertical plane and is adjacent to the front wall 52aof the stationary housing. In order to further reduce the dimensions ofthe printing machine and to allow the platform 4 to move to the positionof FIG. 5, the carriers 23 are rotated in a clockwise direction, asviewed in FIG. 1, to reach the positions shown for the carrier 23 ofFIG. 5. In such position, the corresponding feed roller 22 is located atthe upper end of the associated carrier 23.

If necessary, the entire feed table 2 may be detached from the walls 1,1' merely by sliding the plins 2a, 2b upwardly and through and beyondthe open upper ends of the corresponding vertical slots 1a. In otherwords, the feed table may be stored separately or it may be replaced bya difierently dimensioned feed table with little waste in time and in anexceptionally simple and convenient manner.

Alternatively, the feed table 2 may be removed only in part, forexample, by withdrawing the shaft 3 so that the platform 4- may beseparated from the side walls 2', 2". In the position shown in FIG. 5,the printing machine forms a very compact and completely closed unitwhich protects many of its movable parts against entry of dust, moistureor other foreign matter and which can be stored in a small area orcovered by a comparatively small hood or the like, not shown.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can, by applying current knowledge,readily adapt it for various applications without omitting features.which fairly constitute essential characteristics of the generic andspecific aspects of this invention and, therefore, such adaptationsshould and are intended to be comprehended within the meaning and rangeof equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In an apparatus for feeding sheets to the printing mechanism of aprinting machine, a feed table having a platform for supporting a stackof sheets; a pair of side rails mounted on said feed table for lateralmovement toward and away from the sides of a stack therebetween; meansfor feeding the uppermost sheets from the stack on the platform of saidfeed table; a pair of corner separators each including a lip arranged tooverlie the uppermost sheet of the stack at one front corner thereof anda stop disposed ahead of the corresponding front corner; and couplingmeans articulately connecting each corner separator to one of said siderails in such a way that the corner separators perform a compositepivotal and sliding movement to thereby descend in a plane which issubstantially normal to said platform when the height of the stack onthe platform of said feed table decreases.

2. In an apparatus for feeding sheets to the printing mechanism of aprinting machine, a feed table having a platform for supporting a stackof sheets; a pair of side rails mounted on said feed table for lateralmovement toward and away from the sides of a stack therebetween; meansfor feeding the uppermost sheets from the stack on the platform of saidfeed table; a pair of corner separators each including a lip arranged tooverlie the uppermost sheet of the stack at one front corner thereof anda stop disposed ahead of the corresponding front corner; and couplingmeans articulately connecting each corner separator to one of said siderails in such a way that the corner separators perform a compositepivotal and sliding movement to thereby descend in a plane which issubstantially normal to said platform when the height of the stack onthe platform of said feed table decreases, each coupling meanscomprising a supporting arm having a front end portion connected withthe respective corner separator and a rear end portion articulatelyconnected with the corresponding side rail so that said supporting armsare free to move longitudinally and to pivot with reference to the siderails, and cooperating cam and follower means provided on saidsupporting arms and on said side rails for moving said rear end portionslongitudinally when the front end portions descend by gravity inresponse to decreasing height of the stack.

3. In an apparatus for feeding sheets to the printing mechanism of aprinting machine, a feed table having a platform for supporting a stackof sheets; a pair of side rails mounted on said feed table for lateralmovement toward and away from the sides of a stack therebetween; meansfor feeding the uppermost sheets from the stack on the platform of saidfeed table; a pair of corner separators each including a lip arranged tooverlie the uppermost sheet of the stack at one front corner thereof anda stop disposed ahead of the corresponding front corner; and couplingmeans articulately connecting each corner separator to one of said siderails in such a way that the corner separators perform a compositepivotal and sliding movement to thereby descend in a plane which issubstantially normal to said platform when the height of the stack onthe platform of said feed table decreases, each coupling meanscomprising a horizontal pivot pin secured to the corresponding side railand extending at right angles to the sides of the stack, cam meansprovided on each side rail forwardly of the respective pin, an elongatedsupporting arm having a front end portion connected with thecorresponding corner separator and a rear end portion provided with anelongated slot receiving the corresponding pin so that said supportingarms are movable longitudinally and are free to pivot about said pins,and a follower provided on each arm and arranged to track thecorresponding cam means to thereby guide the respective corner separatorin said plane when the corner separators descend by gravity in responseto decreasing height of the stack.

4. In an apparatus for feeding sheets to the printing mechanism of aprinting machine, a feed table having a platform for supporting a stackof sheets; a pair of side rails mounted on said feed table for lateralmovement toward and away from the sides of a steak therebetween; meansfor feeding the uppermost sheets from the stack on the platform of saidfeed table including feed roller means arranged to rest by gravity onthe uppermost sheet of the stack and carrier means for said feed rollermeans; a pair of corner separators each including a lip arranged tooverlie the uppermost sheet of the stack at one front corner thereof anda stop disposed ahead of the-corresponding front corner; and couplingmeans articulately Connecting each corner separator to one of said siderails in such a way that the corner separators perform a compositepivotal and sliding movement to thereby descend by gravity in a planewhich is substantially normal to said platform when the height of thestack on the platform of said feed table decreases.

5. In an apparatus for feeding sheets to the printing mechanism of aprinting machine, a feed table having a platform for supporting a stackof sheets; a pair of side rails mounted on said feed table for lateralmovement toward and away from the sides of a stack therebetween; meansfor feeding the uppermost sheets from the stack on the platform of saidfeed table; a pair of corner separators each including a lip arranged tooverlie the uppermost sheet of the stack at one front corner thereof anda stop disposed ahead of the corresponding front corner; and couplingmeans articulately connecting each corner sepaartor to one of said siderails in such a way that the corner separators perform a compositepivotal and sliding movement to thereby descend in a plane which issubstantially normal to said platform in response to decreasing heightof the stack, said coupling means comprising elongated supporting armshaving rear end portions articulately connected with said side rails andfront end portions connected with the respective corner separators, anda weight provided on each of said supporting arms to maintain said lipsin contact with the uppermost sheet of the stack.

6. In an apparatus for feeding sheets to the printing mechanism of aprinting machine, a feed table having a platform for supporting a stackof sheets; a pair of side rails mounted on said feed table for lateralmovement toward and away from the sides of a stack therebetween; meansfor feeding the uppermost sheets from the stack on the platform of saidfeed table; a pair of corner separators each including a lip arranged tooverlie the uppermost sheet of the stack at one front corner thereof anda stop disposed ahead of the corresponding front corner; and couplingmeans articulately connecting each corner separator to one of said siderails in such a way that the corner separators perform a compositepivotal and sliding movement to thereby descend in a plane which issubstantially normal to said platform in response to decreasing heightof the stack, said coupling means comprising elongated supporting armshaving rear end portions articulately connected with said side rails andfront end portions adjacent to the corresponding corner separators, andmeans for detachably securing said corner separators to the front endportions of the respective supporting arms.

7. In an apparatus for feeding sheets to the printing mechanism of aprinting machine, a housing; a feed table having a platform forsupporting a stack of sheets, said feed table being mounted in saidhousing to move up and down between a lower end position and a pluralityof additional positions; a pair of side rails extending above saidplatform and mounted on said feed table for lateral movement toward andaway from a stack therebetween; at least one feed member for removingthe uppermost sheets from the stack on said platform; carrier meansmovably secured to said housing and supportingly connected with saidfeed member so as to allow the feed member to remain in contact with theuppermost sheet when the hegiht of the stack decreases; a liftingmechanism operatively connected with said feed member and arranged tolift the feed table in response to descent of said feed member so thatthe uppermost sheet of the stack is normally located at a predeterminedlevel corresponding to an additional position of said feed ta-ble;stationary stop means provided on said housing for arresting saidcarrier means when the feed member descends below said predeterminedlevel; a pair of corner separators each including a lip arranged tooverlie the uppermost sheet of the stack at one front corner thereof anda stop disposed ahead of the corresponding front corner; and couplingmeans articulately connecting each corner separator to one of said siderails in such a way that the corner separators perform a compositepivotal and sliding movement to thereby descend in a plane which issubstantially normal to said platform when the height of the stackdecreases.

8. In an apparatus for feeding sheets to the printing mechanism of aprinting machine, a housing; a feed table having a platform forsupporting a stack of sheets, said feed table being mounted in saidhousing to move up and down between a lower end position and a pluralityof additional positions; a pair of side rails extending above saidplatform and mounted on said feed table for lateral movement toward andaway from a stack therebetween; at least one feed member for removingthe uppermost sheets from the stack on said platform; carrier meansmovably secured to said housing and supportingly connected with saidfeed member so as to allow the feed member to remain in contact with theuppermost sheet when the height of the stack decreases; a liftingmechanism operatively connected With said feed member and arranged tolift the feed table in response to descent of said feed member so thatthe upper most sheet of the stack is normally located at a predeterminedlevel corresponding to an additional position of said feed table;stationary stop means provided on said housing for arresting saidcarrier means when the feed member descends below said predeterminedlevel; a pair of corner separators each including a lip arranged tooverlie the uppermost sheet of the stack at one front corner thereof anda stop disposed ahead of the corresponding front corner; coupling meansarticulately connecting each corner separators to one of said side railsin such a way that the corner separators perform a composite pivotal andsliding movement to thereby descend in a plane which is substantiallynormal to said platform when the height of the stack decreases; andadditional stop means provided on said housing for arresting said cornerseparators when said lips descend below said predetermined level.

9. In an apparatus for feeding sheets to the printing mechanism of aprinting machine; a housing; a feed table including a subframedetachably mounted on said housing and a platform for supporting a stackof sheets, said platform being rotatable in said subframe about atransverse horizontal axis between a substantially vertical idleposition and a substantially horizontal operative position; a pair ofside rails extending above said platform and mounted on said feed tablefor lateral movement toward and away from the sides of a stacktherebetween; means for feeding the uppermost sheets from the stack onsaid platform; a pair of corner separators each including asubstantially horizontal lip arranged to overlie the uppermost sheet ofthe stack at one front corner thereof and a substantially vertical stopdisposed ahead of the corresponding front corner; and coupling meansarticulately connecting each corner separator to one of said side railsin such a way that the corner separators perform a composite pivotal andsliding movement to thereby descend in a plane which is substantiallynormal to said platform when the height of the stack on said platformdecreases.

10. In an apparatus for feeding sheets to the printing mechanism of aprinting machine, a feed table having a platform for supporting a stackof sheets; a pair of mounting means installed on said feed table forlateral movement toward and away from the sides of a stack therebetween;a side rail pivotally secured to each of said mounting means, each ofsaid side rails being movable between an operative position in asubstantially vertical plane and a folded position in which it overliessaid platform; means for feeding the uppermost sheets from the stack onsaid platform; a pair of corner separators each including a lip arrangedto overlie the uppermost sheet of the stack at one front corner thereofand a stop disposed ahead of the corresponding front corner in operativepositions of said side rails; and coupling means articulately connectingeach corner separator to one of said side rails in such a way that thecorner separators perform a composite pivotal and sliding movement tothereby descend in a plane which is substantially normal to saidplatform in response to decreasing height of the stack.

11. A structure as set forth in claim 10, wherein said platform isnormally located in a substantially horizontal plane and wherein saidside rails extend upwardly and beyond said platform at least in saidoperative positions thereof.

12. A structure as set forth in claim 10, wherein each of said cornerseparators is movable between an operative position and an inoperativeposition and wherein said coupling means comprises manually operablehandgrip means for facilitating such movements of said cornerseparators.

13. A structure as set forth in claim 12, wherein each of said couplingmeans further comprises a supporting arm articulately connected with thecorresponding side rail and secured to the respective corner separator,and cooperating cam and follower means provided on said side rails andon said supporting arms for guiding the supporting arms during movementof corner separators between said operative and inoperative positionsthereof.

14. A structure as set forth in claim 13, wherein said handgrip meansconstitute said follower means and extend outwardly from the respectiveside rails.

15. A structure as set forth in claim 12, further comprising blockingmeans for holding said side rails against movement to said foldedpositions in response to move ment of corner separators into saidoperative positions thereof.

'16. In an apparatus for feeding sheets to the printing mechanism of aprinting machine, a housing; a feed table detachably mounted on saidhousing and having a platform for supporting a stack of sheets thereon;a pair of side rails mounted on said feed table for lateral movementtoward and away from the sides of a stack therebetween; means mounted onsaid housing for feeding the uppermost sheets from the stack on saidplatform; a pair of corner separators each including a lip arranged tooverlie the uppermost sheet of the stack at one front corner thereof anda stop disposed ahread of the corresponding front corner; and couplingmeans articulately connecting each corner separator to one of said siderails in such a way that the corner separators perform a compositepivotal and sliding movement to thereby descend in a plane which issubstantially normal to said platform in response to decreasing heightof the stack.

-17. In an apparatus for feeding sheets to the printing mechanism of aprinting machine; a feed table having a platform for supporting a stackof sheets; a transversely extending horizontal spindle axially movablymounted in said feed table; means mounted on said housing for feedingthe uppermost sheets from the stack on said platform; actuating meansoperatively connected with and arranged to move said spindle axially; apair of mounting members mounted on said spindle at the opposite sidesof a stack on said platform and movable laterally toward and away from astack therebetween; a side rail mounted on each of said mounting membersand extending upwardly along the corresponding side of the stack;disengageable clamping means for normally securing said mounting membersto said spindle so as to fix said mounting members and said side railsin selected positions with reference to said spindle; a pair of cornerseparators each including a lip arranged to overlie the uppermost sheetof the stack at one front corner thereof and a stop disposed ahead ofthe corresponding front corner; and coupling means articulatelyconnecting each corner separator to one of said side rails in such a waythat the corner separators perform a composite pivotal and slidingmovement to thereby descend in a plane which is substantially normal tosaid platform in response to decreasing height of the stack.

18. A structure as set forth in claim 17, wherein said spindle comprisesan externally threaded portion and wherein said actuating meanscomprises a knob rotatably mounted in said housing and having aninternally threaded portion mating with said externally threadedportion.

19. A structure as set forth in claim 17, wherein each of said clampingmeans comprises a screw meshing with the corresponding mounting memberand having a tip movable into and out of frictional engagement with saidspindle.

20. A structure as set forth in claim 17, wherein each of said mountingmembers comprises a horizontal pin normal to said spindle and pivotallysupporting the corresponding side rail so that said side rails arefoldable over said platform when a stack is removed therefrom.

2-1. In an apparatus for feeding sheets to the printing mechanism of aprinting machine, a feed table having a platform for supporting a stackof sheets; a pair of mounting means installed on said feed table forlateral movement toward and away from the sides of a stack therebetween;a side rail pivotally secured to each of said mounting means and beingmovable between an operative position in a substantially vertical planeand a folded position in which it overlies said platform; means forfeeding the uppermost sheets from the stack on said platform; a pair ofcorner separators each including a lip arranged to overlie the uppermostsheet of the stack at one front corner thereof and a stop disposed aheadof the corresponding front corner in operative positions of said siderails; coupling means articulately connecting each corner separator toone of said side rails in such a way that the corner separators descendin a plane which is substantially normal to said platform in response todecreasing height of the stack, each of said coupling means comprisingan elongated supporting arm having a front end portion connected withthe respective corner separator and a rear end portion articulatelysecured to the corresponding side rail, each of said supporting armsbeing movable with reference to the corresponding side rail between anoperative position and a retracted position; and blocking means providedon said side rails and arranged to engage the corresponding mountingmeans to prevent folding of side rails in operative positions of saidsupporting arms.

22. A structure as set forth in claim 21, wherein each of said couplingmeans comprises a follower mounted on the corresponding supporting armand cam means provided on the respective side rail for guiding thefollower when the associated supporting arm is moved to said retractedposition thereof, said blocking means comprising levers pivotallysecured to said side rails and normally engaging the correspondingmounting means to prevent movement of side rails to said foldedpositions thereof, said levers being located in the pathway of thecorresponding followers to be disengaged from the associated mountingmeans in response to retraction of said supporting arms.

23. A structure as set forth in claim 22, wherein each of said levers isprovided with a dwell formation which receives the correspondingfollower in retracted position of said supporting arms.

G4. In an apparatus for feeding sheets to the printing mechanism of aprinting machine, a housing including a front wall; a feed table havinga platform for supporting a stack of sheets so that the front side ofthe stack abuts against said front wall, said feed table being mountedin said housing to move up and down between a lower end position and aplurality of additional positions; a pair of side rails extending abovesaid platform and mounted on said feed table for lateral movement towardand away from a stack therebetween; at least one feed member forremoving the uppermost sheets from the stack on said platform; carriermeans movably secured to said housing and supportingly connected withsaid feed member so as to allow the feed member to remain in contactwith the uppermost sheet when the height of the stack decreases;

a lifting mechanism operatively connected with said feed member andarranged to lift the feed table in response to descent of said feedmember so that the uppermost sheet of the stack is normally located at apredetermined level corresponding to an additional position of said feedtable; stationary stop means provided on said housing for arresting saidcarrier means when the feed member descends below said predeterminedlevel; a pair of corner separators each including a lip arranged tooverlie the uppermost sheet of the stack at one front corner thereof anda stop disposed ahead of the corresponding front corner, said stopsbeing located in a plane located forwardly of said front wall so thatthe front wall is nearer to the front side of the stack; and couplingmeans articulately connecting each corner separator to one of said siderails in such a way that the corner separators perform a compositepivotal and sliding movement to thereby descend in a plane which issubstantially normal to said platform when the height of the stackdecreases.

25. In an apparatus for feeding sheets to the printing mechanism of aprinting machine, a housing; a feed table mounted in said housing andhaving a platform for supporting a stack of sheets; a pair of side railsmounted on said feed table (for lateral movement toward and away fromthe sides of a stack therebetween; a pair of carrier means pivotallysupported by said housing means above the uppermost sheet of the stackso as to be rotatable about a fixed transverse horizontal axis; at leastone intermittently driven feed member mounted between said carrier meansfor feeding the uppermost sheets from the stack on said platform, saidfeed member being rotatable about a transverse axis spaced from saidfixed axis and each of said carrier means having a plurality of holeslocated at different distances from said fixed axis, the holes in one ofsaid carrier means being aligned with the holes in the other carriermeans; a weight having end portions removably received in a pair ofaligned holes to bias said feed member against the uppermost sheet ofthe stack whereby the pressure upon the uppermost sheet changes when theend portions of said weight are inserted into another pair of alignedholes; a pair of corner separators each including a lip arranged tooverlie the uppermost sheet of the stack at one front corner thereof anda stop disposed ahead of the corresponding front corner; and couplingmeans articulately connecting each corner separator to one of said siderails in such a way that the corner separators descend in a plane whichis substantially normal to said platform when the height of the stack onsaid platform decreases.

26. in an apparatus for feeding sheets to the printing mechanism of aprinting machine, a housing; a feed table mounted on said housing andhaving a platform for supporting a stack of sheets; a pair of carrierssupported by said housing for pivotal movement about a fixed transversehorizontal axis which is located at a level above the uppermost sheet ofthe stack; at least one intermittently driven feed roller mountedbetween said carriers for feeding the uppermost sheets from the stack onsaid platform, said feed roller being rotatable about a secondtransverse horizontal axis spaced from said fixed axis, each of saidcarriers having a plurality of holes located at different distances fromsaid fixed axis and each hole of one carrier being aligned with a holeof the other carrier; and a weight having end portions removablyreceived in a pair of aligned holes to bias said feed roller against theuppermost sheet of the stack, said weight being insertable into anyselected pair of aligned holes to thereby determine the pressure betweensaid roller and the uppermost sheet of the stack.

27. A structure as set forth in claim 26, wherein said end portions arepins extendable into selected pairs of aligned holes and wherein saidweight comprises a spring for biasing said pins outwardly.

28. In an apparatus for feeding sheets to the printing mechanism of aprinting machine, in combination, a feed table having a platform forsupporting a stack of sheets; a pair of side rails mounted on said feedtable, at least one of said side rails being movable toward and awayfrom the corresponding side of the stack on said platform; a pair ofcorner separators each including a lip arranged to overlie the uppermostsheet of the stack at one front corner thereof and a stop disposed aheadof the corresponding front corner; and coupling means articulatelyconnecting each corner separator to one of said side rails in such a waythat the corner separators perform a composite pivotal and slidingmovement to there-by be guided for movement in a plane which issubstantially normal to the platform.

29. A structure as set forth in claim 28, wherein each of said couplingmeans comprises a supporting arm having a front end portion connectedwith the respective corner separator and a rear end portion articulatelyconnected with the corresponding side rail so that said supporting armsare free to move longitudinally and to pivot with reference to the siderails, and cooperating cam and follower means provided on saidsupporting arms and on said side rails for moving said supporting armslongitudinally in response to pivoting thereof or vice versa.

30. A structure as set forth in claim 29, wherein said side rails areprovided with additional cam means arranged to be tracked by saidfollower means for guiding said supporting arms into retracted positionsin which said corner separators are adjacent to said platform.

References Cited by the Examiner UNITED STATES PATENTS 2,284,841 6/1942Phillips 271-36 2,826,412 3/1952 Haberland 271 61 2,893,729 7/1959|Perzentka 271-21 2,922,644 1/1960 Perzentka 271 39 3,083,962 4/1963Eichorn 271-36 M. HENSON WOOD, JR., Primary Examiner.

R. A. SCI-IACHER, Assistant Examiner.

28. IN AN APPARATUS FOR FEEDING SHEETS TO THE PRINTING MECHANISM OF APRINTING MACHINE, IN COMBINATION, A FEED TABLE HAVING A PLATFORM FORSUPPORTING A STACK OF SHEETS; A PAIR OF SIDE RAILS MOUNTED ON SAID FEEDTABLE, AT LEAST ONE OF SAID RAILS BEING MOVABLE TOWARD AND AWAY FROM THECORRESPONDING SIDE OF THE STACK ON SAID PLATFORM; A PAIR OF CORNERSEPARATORS EACH INCLUDING A LIP ARRANGED TO OVERLIE THE UPPERMOST SHEETOF THE STACK AT ONE FRONT CORNER THEREOF AND A STOP DISPOSED AHEAD OFTHE CORRESPONDING FRONT CORNER; AND COUPLING MEANS ARTICULATELYCONNECTING EACH CORNER SEPARATOR TO ONE OF SAID SIDE RAILS IS SUCH A WAYTHAT THE CORNER SEPARATORS PERFORM A COMPOSITE PIVOTAL AND SLIDINGMOVEMENT TO THEREBY BE GUIDED FOR MOVEMENT IN A PLANE WHICH ISSUBSTANTIALLY NORMAL TO THE PLATFORM.